How to Install Windows 7 or Windows 8 from a USB Drive

The Windows Operating system is generally available in DVDs, but at times, we might want to install Windows from an ISO file on our hard disk, instead of a DVD. The only problem is that we cannot read an ISO file without starting Windows first. In this guide, we will see how to create a bootable USB disk from an ISO file of Windows 7 or Windows 8. This will allow us to install Windows, just as we do using a DVD.

Creating a bootable Windows 7 or Windows 8 disk

Step 2: Go to Start menu, type in cmd and right-click on cmd.exe search result as shown in the image. From the right click context menu, select the Run as Administrator option.

Step 3: Type diskpart and press enter. Diskpart is a nifty utility to manage partitions and disk drives in Windows.

Step 4: When Diskpart starts, the command prompt will change to a DISKPART prompt.

Now, type the list volume command. This will list out all the disk volumes on your computer.

Step 5: From the list above, you have to select the appropriate drive by looking at the details given as a result of this command. In this screenshot, I have selected the disk with the size of 7399 MB, because I am using an 8 GB USB drive.

[It is very important that you select the right drive. This step can spoil your computer’s hard-disk partitions, if done wrong.]

Issue the select volume command as shown in the screenshot below. The select volume command has to be supplied with a drive number. This is the number listed on the first column of the list volume command result, for a drive you want to use. Run the command as shown, replacing with your appropriate drive number.

Step 6: Now that we have selected a drive, it is time to run the clean command. This will clean the drive of all partitions and prepare it for a fresh partition structure.

Step 7: Now, we will create a primary partition, as all bootable drives should have primary partitions. Issue the command create partition primary.

Step 8: The heart of any bootable disk is the boot sector. For the boot sector to be written into the primary partition, it has to be active. Mark the partition as active by issuing the active command.

Step 9: Now, we have to format the disk. Windows accepts only NTFS format disk partitions for a boot sector. Issue the command format fs=NTFS command. Once the format completes, close command window.

Step 10: This is another critical part of all the steps.

[ I assume you have already extracted your Windows ISO file and copied its contents somewhere.]

Navigate to the boot folder of the extracted ISO. Now, shift+right click in an empty area as shown and click on Open command window here.

In that command window, issue the command bootsect.exe /nt60 with the appropriate drive letter as shown below. I have given J: because after formatting, my USB drive appeared as J drive. Use your appropriate USB drives’s letter.

Step 11: Navigate to the root folder where your ISO is extracted in Windows explorer. it should have folders like boot, efi, sources, support, upgrade and files like bootmgr, autorun.inf. Select all these files and folders, and copy them into the thumb drive.

Congratulations! You are ready with a bootable USB drive.

Follow the steps serially, without skipping any of them, or jumping back and forth. Share your experience with us.